High-frequency signals transmitted on separate lines within a bundle of twisted pair copper cables may interfere with each other. The nature and degree of interference may vary depending on the nature of the cabling and the characteristics of the communication. For this reason, national and international standards and regulations may govern transmissions across trunk lines within communication networks. For example, transmissions across trunk lines within a proprietary network interfacing directly with a public switched telephone network (PSTN) may be regulated by standards adopted by the American National Standards Institute (ANSI) or the European Telecommunications Standards Institute (ETSI), depending on the location of the PSTN. It may therefore be necessary for a switch using such a network to communicate with customer premises equipment (CPE) devices within the network using a power spectral density (PSD) that complies with ANSI or ETSI standards. In contrast, transmissions across lines within a proprietary network coupled to a PSTN via a private branch exchange (PBX) may be unconstrained by such standards. Therefore, a switch supporting a network coupled to a PSTN via a PBX may be free to communicate with CPE devices within the network using a PSD that provides a higher bit rate or greater reliability than PSDs that comply with ANSI or ETSI standards.
Traditionally, field-replaceable line cards have been used to provide switches that may support communication in different spectra. However, the use of line cards has several drawbacks. For example, the use of line cards adds to costs associated with setting up and operating switches and increases the size of switch “footprints.” Moreover, a single line card may support communication in only one power spectrum. Network administrators may therefore have to replace line cards supporting communication between the switch and CPE devices to effect a change in the PSD used for data communication within the network.